package inherit;

import java.util.ArrayList;
import java.util.List;

public class InheritTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		InheritLevel1 il1 = new InheritLevel3();
		il1.f();
		
		List<Object> l = new ArrayList<Object>();
		
		l.add(null);
		l.add(null);
		l.add(null);
		l.remove(null);
		System.out.println(l.size());
	}

}

interface InheritLevel1{
	public void f();
}

abstract class InheritLevel2 implements InheritLevel1{
	public abstract void f();
}

class InheritLevel3 extends InheritLevel2{

	@Override
	public void f() {
		System.out.println("InheritLevel3");
	}
	
}